The rank was first introduced into the Metropolitan Police in 1868 and was first used by Adolphus Williamson, the first head of the Detective Branch (later the Criminal Investigation Department). When Williamson was promoted to Superintendent shortly afterwards, three of his Inspectors were promoted to Chief Inspector and the rank was firmly established. In 1869 it was also introduced as a uniformed rank, with the senior assistant to the Divisional Superintendent being given the rank. The rank subsequently spread to other police forces.
From 1933, every Metropolitan Police division had two Chief Inspectors: Chief Inspector (Administration) and Chief Inspector (Crime) (the latter also being an administrative officer and not replacing the Divisional Detective Inspector). In 1949, Sub-Divisional Inspectors were also regraded as Chief Inspectors.
Today, the function of Chief Inspectors varies from force to force. They may assist Basic Command Unit (BCU) commanders, command smaller units, or fill various staff posts.
Detective Chief Inspector (DCI) is usually the minimum rank held by a Senior Investigating Officer (SIO), who heads major investigations (into murder, for example), and a pool of these officers usually works out of force headquarters or major police stations. The senior Criminal Investigation Department (CID) officer in each BCU usually also holds this rank.
The rank badge of a Chief Inspector is three stars ("pips") worn on the epaulettes. This is the same badge as a Captain in the British Army.
Chief Inspector was one of the ranks proposed for abolition in the police organisational reforms of the 1990s, but all forces still retain it.
The taking of samples for analysis constitutes their chief duty, though special investigations in collaboration with the chemists are also made, and factories where articles of food or drugs are prepared, are also inspected.
The ChiefInspector has an assistant who visits the various stations throughout the country from time to time in a supervisory capacity, suggesting improvements, criticising and reporting confidentially to the ChiefInspector, whose place he assumes during the illness or absence of the latter.
Every inspector is assigned to a particular city which is considered his official station or permanent headquarters and is the central or principal point of the territory covered by him during the year.